i cleaned out my tank the other day, and woke up to find my betta hiding. i could tell he wasn't feeling well, especially with the way that he was acting. he would hide a lot. i then remembered that i forgot the de-cholorinator!!! WHOOPS... so i poured some in, and he's just lying on the bottom now (alive!)... i think that if he's made it this far, he will do fine. he looks fine on the outside. not much else i can really do... any advice, suggestions? thanks a bunch!

How long was he in the unconditioned water? If it's only been a few days at most, he's probably in some shock and will hopefully recover. Longer than that and I'm not sure what the long-term prognosis would be. Keep an eye out for rapid breathing and movement of his gills because these would be signs of chemical poisoning. If you see these signs, do another water change (with the dechlorinator of course ^_^).

I did this once by accident too, oops! My fish was only in the cholorinated water for about 2 hours before i noticed, and he was still really stressed out for about a day after that. So it might take yours a few days, but i bet he will be fine! Just keep a close eye on him! Don't feel too bad, mistakes happen and you were trying to do something nice for him by cleaning his tank!